graphml2gv: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/graphml2gv - from package: graphviz

You may install the required package with command apt-get install {package}

Error in other languages:
graphml2gv: bevel nie gevind nie
graphml2gv: comandă negăsită
graphml2gv: comando não encontrado
graphml2gv: commande introuvable
graphml2gv: command not found
graphml2gv: käsku ei ole
graphml2gv: không tìm thấy lệnh
graphml2gv: komanda nerasta
graphml2gv: Kommando nicht gefunden.
graphml2gv: kommandot finns inte
graphml2gv: komut yok
graphml2gv: nie znaleziono polecenia
graphml2gv: níor aimsíodh an t-ordú
graphml2gv: no se encontró la orden
graphml2gv: no s'ha trobat l'ordre
graphml2gv: opdracht niet gevonden
graphml2gv: parancs nem található
graphml2gv: perintah tidak ditemukan
graphml2gv: príkaz nenájdený
graphml2gv: příkaz nenalezen
graphml2gv: команда не найдена
graphml2gv: командата не е открита
graphml2gv: 命令找不到
graphml2gv: コマンドが見つかりません